Herpetological Review 39(3), 2008 310 Herpetological Review, 2008, 39(3), 310–314. © 2008 by Society for the Study of Amphibians and Reptiles Finding a Needle in a Haystack: New Methods of Locating and working with Rhinoceros Vipers (Bitis rhinoceros) JOHANNES PENNER Department of Animal Ecology and Tropical Biology, University of Würzburg Biocenter, Am Hubland, D-97074 Würzburg, Germany e-mail: penner@biozentrum.uni-wuerzburg.de CéCILE FRUTEAU Laboratoire d’Ethologie des Primates, CEPE, 7 rue de l’Université 67000 Strasbourg, France FRIEDERIKE RANGE Department of Psychology, University of Pennsylvania 3815 Walnut Street, Philadelphia, Pennsylvania 19104-6169, USA Current address: Department of Neurobiology and Cognition Research University of Vienna, Althanstrasse 14, A-1091 Wien, Austria and MARK-OLIVER RöDEL Department of Animal Ecology and Tropical Biology, University of Würzburg Biocenter, Am Hubland, D-97074 Würzburg, Germany Current address: Museum of Natural History, Humboldt University Berlin, Herpetology, Invalidenstrasse 43, D-10115 Berlin, Germany e-mail: mo.roedel@mseum.hu-berlin.de Large snake species are important predators in their ecosystems (Dodd 1987; Greene 1997; Lawson and Klemens 2001). Rhinoceros Vipers (Viperidae: Bitis rhinoceros, Schlegel, 1855) are among the biggest and most massive venomous snakes (Phelps 1981). Taxonomically they are closely related to the Gaboon Viper, Bitis gabonica (Duméril et al. 1854), and were long considered to be only a subspecies of the latter. A sister species to these two taxa is the Nose-horned Viper, Bitis nasicornis (Calvete et al.